if you're into architecture, Chicago is world famous for early 20th century architecture. The Chicago Architectural Foundation has TONS of walking, bus, and boat tours. We've been on several - they've all been excellent.
Art Institute is great if you're into art; Field Museum is great if you're into natural history. We also do a lot of just walking around when we're in Chicago (I live two hours from there, so we do weekends there several times a year).
the Drake is pretty far north in the Loop - north of Loyola. The area around the Loyola campus is nice. But go beyond that and walk down Michigan Ave - so much there.
we've been to so many restaurants, but I can't think of any one particular one to recommend - you'll stumble upon tons just walking around. We usually try to hit ethnic places, usually. Scoot over to some of the other streets that parallel Michigan Ave - there are lots of restaurants over there as well. You could always pick some cuisine and do a search on that. We've been to Colombian places, Argentine places, Turkish places, Middle Eastern places, Cajun places, pizza places, delis, so many.....they really have everything there.
P.S. there's a Nutella Cafe on Michigan Ave. Might want to avoid that one! (it's great but...Nutella - you'll gain 10 lbs just walking in the door!)